1. Field of the Invention
The present invention relates to a method of and an apparatus for manufacturing a ceramic layered product.
2. Description of the Background Art
In order to manufacture a multilayer ceramic electronic component such as a multilayer ceramic capacitor, a multilayer inductor or a multilayer circuit board, for example, raw ceramic sheets are stacked with each other to prepare a ceramic layered product. For example, a ceramic layered product for a multilayer ceramic capacitor has generally been obtained by the following method or apparatus:
As shown in FIG. 10, a previously prepared mother ceramic sheet is drawn out from a sheet drawing station 1 to an electrode printing/cutting station 2, where the mother ceramic sheet is punched while electrodes are simultaneously printed on the ceramic sheets, which are punched out from the mother ceramic shaft. After the punching step, the mother ceramic sheet is discharged as a scrap sheet, while the ceramic sheets provided with the electrodes are dried in a drying station 3, and thereafter stored in a sheet storage station 4.
The stored ceramic sheets are selected to provide the characteristics, such as capacitance, required for the multilayer ceramic capacitor to be obtained. They are stacked and aligned with each other on the basis of their end surfaces. Then the aligned ceramic sheets are inserted in a stacking jig, and subjected to press working.
However, the aforementioned system has the following problems:
(1) A large space is required in order to store the punched ceramic sheets.
(2) Since the electrodes are printed simultaneously with the cutting of the ceramic sheets through a mechanical positioning mechanism, electrode positions are not much dispersed in the same type of electrode patterns. When the electrode patterns are exchanged, however, the electrode positions are apt to be dispersed between the different types of electrode patterns.
(3) When the electrode patterns are exchanged, it takes much time to locate the electrode patterns on cutting positions.
(4) Since the ceramic sheets are aligned with each other on the basis of their end surfaces, the electrode positions of the aligned ceramic sheets still remain dispersed resulting from the problem described above in paragraph (2), to cause dispersion in the capacitances of the multilayer ceramic capacitors obtained by this method. Further, the electrode positions may also be dispersed by the aligning operation itself.
(5) If static electricity is generated between the ceramic sheets, or if the ceramic sheets have small thicknesses, it is difficult to align the ceramic sheets.
(6) The aligned ceramic sheets may be displaced from each other when they are inserted in the stacking jig.
Due to such problems of the system shown in FIG. 10, it has been difficult to stack the ceramic sheets with high accuracy.
In order to solve the problems in relation to handling the ceramic sheets in the aforementioned system, the applicant has proposed the following system, which is not yet known in the art:
As shown in FIG. 11, a sheet drawing station 5 is continuously coupled through an electrode printing station 6, a drying station 7 and a cutting/stacking station 8 to a scrap sheet winding station 9. A ceramic layered product is taken out from the cutting/stacking station 8. The feature of this system resides in that the electrode printing station 6 and the drying station 7 are provided in front of the cutting/stacking station 8.
However, the aforementioned system has the following problems:
(1) This system can merely manufacture the same type of ceramic layered products in relation to electrode patterns.
(2) When the items are switched, it takes much time for setup operations such as exchange of print patterns, exchange of sheets and the like.
(3) The system requires leader and end sheets extending beyond the length of the apparatus or the production line, to cause reduction of the material yield.
(4) Due to the continuous steps, complicated operations are required for dealing with possible defective prints and returning to the normal operation.
(5) In order to obtain a ceramic layered product for a multilayer ceramic capacitor, in particular, it is necessary to frequently drive and stop a printer in order to continuously obtain both ceramic sheets provided with electrodes and those provided with no such electrodes. Thus, printing accuracy is deteriorated due to irregular printing conditions.
(6) This system is unsuitable for multi-item dab production because of the problems mentioned above in paragraphs (1) to (3), although the same is suitable for mass production with small setup changes.